Re: [libvirt] [PATCH] daemon: Plug memory leaks
On Thu, Apr 12, 2012 at 03:24:08PM +0800, Alex Jia wrote:
Detected by valgrind. Leaks are introduced in commit 6e6e9be.
* daemon/libvirtd-config.c (macro GET_CONF_STR): fix memory leaks.
How to reproduce?
% make && make -C tests check TESTS=libvirtdconftest
% cd tests && valgrind -v --leak-check=full ./libvirtdconftest
actual result:
==11008== 185 bytes in 5 blocks are definitely lost in loss record 3 of 5
==11008== at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
==11008== by 0x39CF07F6E1: strdup (strdup.c:43)
==11008== by 0x406626: daemonConfigLoadOptions (libvirtd-config.c:438)
==11008== by 0x406800: daemonConfigLoadData (libvirtd-config.c:492)
==11008== by 0x403CCF: testCorrupt (libvirtdconftest.c:110)
==11008== by 0x404FAD: virtTestRun (testutils.c:145)
==11008== by 0x403A34: mymain (libvirtdconftest.c:219)
==11008== by 0x404687: virtTestMain (testutils.c:700)
==11008== by 0x39CF01ECDC: (below main) (libc-start.c:226)
==11008==
==11008== LEAK SUMMARY:
==11008== definitely lost: 185 bytes in 5 blocks
Signed-off-by: Alex Jia <ajia(a)redhat.com>
---
daemon/libvirtd-config.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/daemon/libvirtd-config.c b/daemon/libvirtd-config.c
index 4d041f0..0a4323a 100644
--- a/daemon/libvirtd-config.c
+++ b/daemon/libvirtd-config.c
@@ -152,6 +152,7 @@ checkType (virConfValuePtr p, const char *filename,
virReportOOMError(); \
goto error; \
} \
+ VIR_FREE(data->var_name); \
} \
} while (0)
Errr, no. Please look at the context of what's going on, rather than
just blindly adding code to free a block at the point where valgrind
shows the allocation.
The full context to this diff
#define GET_CONF_STR(conf, filename, var_name) \
do { \
virConfValuePtr p = virConfGetValue (conf, #var_name); \
if (p) { \
if (checkType (p, filename, #var_name, VIR_CONF_STRING) < 0) \
goto error; \
VIR_FREE(data->var_name); \
if (!(data->var_name = strdup (p->str))) { \
virReportOOMError(); \
goto error; \
} \
} \
} while (0)
Your suggested change means we would be free'ing the config file before
we have even used it.
If you look at this line:
==11008== by 0x406626: daemonConfigLoadOptions
(libvirtd-config.c:438)
You'll see it matches:
GET_CONF_STR (conf, filename, host_uuid);
There are no leak reports for other uses of GET_CONF_STR, so this suggests
that 'host_uuid' is not being freed. Check daemonConfigFree and you'll see
this is indeed missing
Daniel
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